Lux & Non-Lux: Nav 101?

[JeepTherapy]

Hi everyone - I searched through the archives & it's not really clear. I would like to install a GM in-dash Nav unit, preferrably with touchscreen. I have a 2005 GMC Sierra SLE without a Bose system - just a CD / Cassette. I bought it a week ago, my first GM truck & I really like it.

 

First Question: What's Lux & do I have it?

Second Question: What's a Y91 RPO indicate?

Third Question: Is a factory Delphi / GM Nav system compatible with my truck?

 

I know about the Eclipse, Pioneer & other aftermarket in-dash Nav units, but I'd like to keep the truck looking as close to stock as possible.

 

Thanks to everyone for the help.

 

Jeff